Field-plated AlGaN/GaN HEMTs with power density of 9.1 W/mm at 18 GHz

AlGaN/GaN high electron mobility transistors (HEMTs) are excellent candidates for high power and high frequency applications at room and elevated temperatures due to their superior material properties. As a result of improved material growth and processing technologies, microwave power densities have been demonstrated that are five to ten times greater than that of corresponding GaAs-based devices. Though GaN HEMTs using field plate have demonstrated power densities as high as 32W/mm at 4 GHz, however to date, there have been only few reports on field-plated devices up to X band [1,2]. In this paper, we present record power performance of AlGaN/GaN HEMTs on 6H-SiC substrates at 18 GHz. A CW output power density of 9.1 W/mm with a gain of 5.8 dB and power added efficiency of 23.7 % were achieved.